Natural gas gathering, processing and transportation remain a focal point for Oneok Inc.’s growth plans despite recently closing a major acquisition focused on crude oil and refined products.

Oneok saw 12% year/year growth in natural gas processing volumes during the third quarter, CEO Pierce Norton said during a conference call to discuss the Tulsa-based midstreamer’s quarterly results. Oneok continues to see “robust producer activity across our operations with North Dakota natural gas production reaching a new all-time high in August,” Norton added.

The company’s natural gas and natural gas liquids infrastructure serves a wide swath of the Lower 48 including the Williston, Powder River, Denver-Julesburg and Permian basins. Oneok also serves Oklahoma’s South Central...